feat: add DNS server routes to WireGuard profiles and gateway firewall rules

Add mergeProfileAllowedIPs function to combine policy destinations with DNS server routes in device enrollment and rotation. Add dnsServerRoute helper to convert DNS server IPs to /32 CIDR notation. Update BuildSyncBundle query to include gateway DNS servers in peer data. Add DNSServers field to wireguard.Peer struct. Update gateway nftables configuration to allow UDP/TCP port 53 traffic from assigned IPs to DNS servers before

backend/internal/device/service.go

@@ -2,6 +2,7 @@ package device
 
 import (
 	"context"
+	"strings"
 
 	"github.com/google/uuid"
 
@@ -61,11 +62,12 @@ func (s *Service) Enroll(ctx context.Context, userID uuid.UUID, input EnrollRequ
 	if len(destinations) == 0 {
 		destinations = []string{"172.16.10.0/24"}
 	}
+	profileAllowedIPs := mergeProfileAllowedIPs(destinations, selectedGateway.DNSServers)
 
 	enrollment.Peer = PeerView{
 		AssignedIP: assignedIP,
 		DNSServers: selectedGateway.DNSServers,
-		AllowedIPs: destinations,
+		AllowedIPs: profileAllowedIPs,
 		Gateway: GatewayView{
 			ID:        selectedGateway.ID,
 			Name:      selectedGateway.Name,
@@ -90,7 +92,7 @@ func (s *Service) Enroll(ctx context.Context, userID uuid.UUID, input EnrollRequ
 			DNSServers:       selectedGateway.DNSServers,
 			ServerPublicKey:  selectedGateway.PublicKey,
 			ServerEndpoint:   selectedGateway.Endpoint,
-			AllowedIPs:       destinations,
+			AllowedIPs:       profileAllowedIPs,
 			PersistentKeepal: 25,
 		}),
 	}
@@ -149,6 +151,7 @@ func (s *Service) Rotate(ctx context.Context, deviceID uuid.UUID) error {
 }
 
 func withDebugProfile(enrollment EnrollmentResponse) EnrollmentResponse {
+	profileAllowedIPs := mergeProfileAllowedIPs(enrollment.Peer.AllowedIPs, enrollment.Peer.DNSServers)
 	enrollment.Profile = ProfileView{
 		Format: "wireguard",
 		Content: profile.BuildWireGuardConfig(profile.BuildInput{
@@ -157,9 +160,51 @@ func withDebugProfile(enrollment EnrollmentResponse) EnrollmentResponse {
 			DNSServers:       enrollment.Peer.DNSServers,
 			ServerPublicKey:  enrollment.Peer.Gateway.PublicKey,
 			ServerEndpoint:   enrollment.Peer.Gateway.Endpoint,
-			AllowedIPs:       enrollment.Peer.AllowedIPs,
+			AllowedIPs:       profileAllowedIPs,
 			PersistentKeepal: 25,
 		}),
 	}
 	return enrollment
 }
+
+func mergeProfileAllowedIPs(destinations []string, dnsServers []string) []string {
+	seen := make(map[string]struct{}, len(destinations)+len(dnsServers))
+	merged := make([]string, 0, len(destinations)+len(dnsServers))
+
+	for _, destination := range destinations {
+		destination = strings.TrimSpace(destination)
+		if destination == "" {
+			continue
+		}
+		if _, exists := seen[destination]; exists {
+			continue
+		}
+		seen[destination] = struct{}{}
+		merged = append(merged, destination)
+	}
+
+	for _, dnsServer := range dnsServers {
+		route := dnsServerRoute(dnsServer)
+		if route == "" {
+			continue
+		}
+		if _, exists := seen[route]; exists {
+			continue
+		}
+		seen[route] = struct{}{}
+		merged = append(merged, route)
+	}
+
+	return merged
+}
+
+func dnsServerRoute(value string) string {
+	value = strings.TrimSpace(value)
+	if value == "" {
+		return ""
+	}
+	if strings.Contains(value, "/") {
+		return value
+	}
+	return value + "/32"
+}

backend/internal/gateway/repository.go

@@ -91,9 +91,11 @@ func (r *PGRepository) BuildSyncBundle(ctx context.Context, gatewayID uuid.UUID)
 			d.id,
 			wp.public_key,
 			set_masklen(wp.assigned_ip, 32)::text,
-			coalesce(array_agg(distinct pd.destination::text) filter (where pd.destination is not null), '{}')
+			coalesce(array_agg(distinct pd.destination::text) filter (where pd.destination is not null), '{}'),
+			coalesce(g.dns_servers, '{}')::text[]
 		from devices d
 		join wireguard_peers wp on wp.device_id = d.id and wp.deleted_at is null
+		join gateways g on g.id = d.gateway_id
 		left join group_memberships gm on gm.user_id = d.user_id
 		left join policy_targets pt on (
 			(pt.target_type = 'device' and pt.target_id = d.id) or
@@ -102,7 +104,7 @@ func (r *PGRepository) BuildSyncBundle(ctx context.Context, gatewayID uuid.UUID)
 		)
 		left join policy_destinations pd on pd.policy_id = pt.policy_id
 		where d.gateway_id = $1 and d.deleted_at is null and d.status = 'active'
-		group by d.id, wp.public_key, wp.assigned_ip
+		group by d.id, wp.public_key, wp.assigned_ip, g.dns_servers
 	`, gatewayID)
 	if err != nil {
 		return wireguard.GatewayBundle{}, err
@@ -112,7 +114,7 @@ func (r *PGRepository) BuildSyncBundle(ctx context.Context, gatewayID uuid.UUID)
 	for rows.Next() {
 		var peer wireguard.Peer
 		var deviceID uuid.UUID
-		if err := rows.Scan(&deviceID, &peer.PublicKey, &peer.AssignedIP, &peer.AllowedDestinations); err != nil {
+		if err := rows.Scan(&deviceID, &peer.PublicKey, &peer.AssignedIP, &peer.AllowedDestinations, &peer.DNSServers); err != nil {
 			return wireguard.GatewayBundle{}, err
 		}
 		peer.DeviceID = deviceID.String()

backend/internal/wireguard/types.go

@@ -5,6 +5,7 @@ type Peer struct {
 	PublicKey           string   `json:"public_key"`
 	AssignedIP          string   `json:"assigned_ip"`
 	AllowedDestinations []string `json:"allowed_destinations"`
+	DNSServers          []string `json:"dns_servers"`
 }
 
 type GatewayBundle struct {